Effect of Al Content on Microstructure and Mechanical Property of Nanocomposite TiAlSiN Thin Films.

TiAlSiN thin films exhibit high hardness due to the multicomponent and multiphase structures. Effects of Si on TiAlSiN microstructure and mechanical properties have been well studied. However, there is insufficient information on the effects of Al. Thus, in this work, Al-contained nanocomposite nc-TiN/a-SiNx thin films with Al up to 10 at.% were prepared by magnetron co-sputtering Ti, Al and Si3N4 targets in Ar/N2 gas atmosphere. The effects of Al on TiAlSiN microstructure and mechanical property were well studied. Adjusting Al/(Ti+Al) target power ratio tuned chemical composition, microstructure and consequently mechanical properties. With increase of Al/(Ti+Al) target power ratio from 0 to 0.2, Al content increased from 0 to 10 at.%. X-ray photoelectron spectroscope results showed that aluminum nitride was formed. X-ray diffraction results confirmed that the nanocrystalline phase TiN was with Si and Al in its structure, or (Ti, Al, Si) N. The matrix was amorphous silicon nitride containing aluminum nitride. Nanoindentation hardness of the thin films remained at about 28 GPa till Al addition was increased to 3.1 at.%.

K-doped Li2ZnTi3O8/C as an efficient anode material with high performance for Li-ion batteries.

Li2ZnTi3O8/C and Li1.9K0.1ZnTi3O8/C were successfully synthesized using the sol-gel method. Doping K apparently yielded a wider tunnel, helpful for increasing the rate of transport of lithium ions, and furthermore yielded excellent electrochemical properties. The first discharge capacity for Li1.9K0.1ZnTi3O8/C was 352.9 mA h g-1 at a current density of 200 mA g-1. Li1.9K0.1ZnTi3O8/C also performed stably, retaining a capacity of 323.7 mA h g-1 at the 100th cycle, indicative of its excellent cycling properties. In the rate performance test, Li1.9K0.1ZnTi3O8/C showed at the first cycle a high discharge capacity of 379.5 mA h g-1 for a current density of 50 mA g-1 and a capacity of 258.9 mA h g-1 at 1000 mA g-1. The results indicated that K-doping should be considered a useful method for improving electrochemical performances.

ZrO2 coated Li1.9K0.1ZnTi3O8 as an anode material for high-performance lithium-ion batteries.

The Li1.9K0.1ZnTi3O8@ZrO2 (1 wt%, 3 wt%, and 5 wt%) anode material was synthesized by doping Li2ZnTi3O8 with potassium and coating ZrO2, where the ZrO2 coating layer was prepared by citric acid and zirconium acetate, and the potassium source was KCl. When the added ZrO2 amount is 3%, the material has the most uniform size, reduced polarization, and reduced charge transfer resistance, and the specific capacity of LKZTO@ZrO2 (3 w%) was 361.5 mA h g-1 at 200 mA g-1 at the 100th cycle, which is higher than that of LKZTO, of 311.3 mA h g-1. The specific capacities of LKZTO@ZrO2 (3 w%) at 50, 100, 200, 500, and 1000 mA g-1 after 10 cycles were 424.9, 410.7, 394.1, 337.6 and 270.6 mA h g-1, indicating that LKZTO@ZrO2 (3 w%) has excellent electrochemical performance.

Research Progress on Na3V2(PO4)3 Cathode Material of Sodium Ion Battery.

Sodium ion batteries (SIBs) are one of the most potential alternative rechargeable batteries because of their low cost, high energy density, high thermal stability, and good structure stability. The cathode materials play a crucial role in the cycling life and safety of SIBs. Among reported cathode candidates, Na3V2(PO4)3 (NVP), a representative electrode material for sodium super ion conductor, has good application prospects due to its good structural stability, high ion conductivity and high platform voltage (~3.4 V). However, its practical applications are still restricted by comparatively low electronic conductivity. In this review, recent progresses of Na3V2(PO4)3 are well summarized and discussed, including preparation and modification methods, electrochemical properties. Meanwhile, the future research and further development of Na3V2(PO4)3 cathode are also discussed.

Cr-Doped Li2ZnTi3O8 as a High Performance Anode Material for Lithium-Ion Batteries.

Li2ZnTi2.9Cr0.1O8 and Li2ZnTi3O8 were synthesized by the liquid phase method and then studied comparatively using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), galvanostatic charge-discharge testing, cyclic stability testing, rate performance testing, and electrochemical impedance spectroscopy (EIS). The results showed that Cr-doped Li2ZnTi3O8 exhibited much improved cycle performance and rate performance compared with Li2ZnTi3O8. Li2ZnTi2.9Cr0.1O8 exhibited a discharge ability of 156.7 and 107.5 mA h g-1 at current densities of 2 and 5 A g-1, respectively. In addition, even at a current density of 1 A g-1, a reversible capacity of 162.2 mA h g-1 was maintained after 200 cycles. The improved electrochemical properties of Li2ZnTi2.9Cr0.1O8 are due to its increased electrical conductivity.